Paw Paws (Asimina Triloba) -Canadian Hardiness Zone?

(Question)

Hi! I recently received a catalogue from an Ontario nursary that sells Paws Paws, most of their varieties are listed as ZONE 5 (one is listed as zone 4-5) … OK so I’m in a solid 5b in the very south western tip of the Quebec/Ontario/USA borders (formerly called the Chateuguay Valley). Are these Paw Paws REALLY zone 5 hardy? If so, sure the tree will survive but will the blossoms? Will i get ANY fruit IF the trees actually survive? Can I help it by creating a micro climate of some sort? I am on a farm and I do have a backhoe, if I need it. For all intense and purposes I do not want to grow these as a commercial crop, it is for me personally, more nostalgia from my days of living in New Zealand where I had 3 groups of these and I miss them, along with many of my other plants too. I miss my Feijoas ( Acca sellowiana) had 30+ mature trees (bush) but I doubt I can find one that will grow in less than zone 8 so I will wait for those IF ever I build a greenhouse! To recap Paw Paws: Any chance of getting a handful of fruit from them in a zone 5b with mostly sandy-clay soil some areas mid to heavy clay. Have not done a soil analysis yet, that’s coming. Thank you

(Answer)

Thank you for contacting Toronto Master Gardeners.

The Pawpaw tree, Asimina triloba, is native to the Carolinian Forest which extends up into Canada. Looking through the literature shows that there has been a renewed interest in the tree in the last few years as people become more aware of the benefits to planting native trees.

I am seeing a huge range of zones listed for Pawpaws. Some say you are at the top of the range and some say 5b is too cold. I did see one spot mentioning some varieties can go to zone 4. If you find Pawpaws for sale you would need to see what range is listed to see if it is worth taking a chance on in your garden. Finding a sheltered warmer spot in your yard may help increase  your chances of success. They prefer moist, well drained, acidic soil. The tree has a deep tap root so it is recommended that smaller specimens are used for transplanting. It is not a large tree when fully grown (12-20 feet) but it takes several years for fruit production. You have more chance of pollination if you have more than one specimen. They are pollinated by flies but it sounds like the smell of the flower does a good job of attracting them.You will need to plant the tree so it is in mostly shade when it is young but as it grows it should have access to some sunlight during the day or at least dappled sunlight. You will want to avoid the areas of your yard with heavy clay.

I am including some links below for further reading.

Good luck! Hopefully this can be the first step to growing the plants you miss from New Zealand.

https://caroliniancanada.ca/guide/article/almost-forgotten-carolinian-fruit-20171107

https://www.ontario.ca/page/pawpaw

https://web.extension.illinois.edu/dmp/palette/081019.html